Iced Coffee Experiments

I would drink a lot more iced coffee if it only tasted better and were more convenient. On those particularly hot summer mornings (like today) when I can’t bear the thought of a hot cup of coffee I have in the past made usual-strength French press coffee and poured it into a glass jam-packed with ice cubes. The result is barely tepid, watery, bitter.

Thanks to Twitter (@mattmark in particular) I came across this really interesting process for making iced coffee in large batches that stores and is not nearly as bitter or diluted as hot coffee poured over ice. Follow that link. It’s way beyond my understanding of the chemistry involved in coffee making and the original is intensely detailed.

In summary, the process takes fine-medium (freshly) ground coffee, steeps it in hot water for a minute, and then adds cold water and twelve hours of steeping. Cold-brewed iced coffee is nothing new but as you’ll if you follow that link, some of the desirable flavour compounds are only extracted by hot water.

I get the sense that the original post was geared to a professional audience. I’ve scaled my recipe back to use-at-home levels and I wondered what the cost per serving is and whether this would increase my daily caffeine intake.

For my usual french-press brewed coffee I use about 20 g of coffee (I eyeball it but measured twice for this post) and about 500 g of hot water. I find that a batch of the iced coffee lasts three days; I add about 100 g of ice and 100 g of milk to it. Fifty grams of coffee spread over three days is only about 17 g per day but even with my finely tuned caffeine dependence I don’t notice the difference. I suspect the much longer steeping time may mean that more caffeine is extracted from the beans.

At roughly $15 – $18 for a good pound of coffee in Toronto that puts the daily cost (not including the milk) at about 56 cents.

Cold and Hot Brewed Iced Coffee

Adapted from the recipe on the Beans And Water tumblr. I’ve scaled the volume down and added a pinch of salt to further cut the bitterness but this is a very close adaptation. I strongly encourage you to visit the original and read more of the details.

By brewing hot for a minute and then cold for twelve hours you get iced coffee with the best of both methods.

Yield:500 ml or three servings

50 g coffee, ground fine-medium

100 g hot water, just off the boil

100 g ice

300 g cold, filtered water

pinch salt

Place freshly-ground coffee and a pinch of salt in a sturdy, non-reactive container. Add hot water, swirl or stir with a chopstick so that the water is evenly distributed around the coffee. Steep for one minute.

Strain coffee from grounds and serve with ice and milk or straight up. The original poster thinks the coffee will oxidize well before three weeks. I haven’t noticed any problems over three to five days in the refrigerator.